The shortest war in recorded history occurred on 27 August 1896. Known as the Anglo-Zanzibar War, the reason behind the conflict was the death of Sultan Hamad bin Thuwaini two days earlier. Contrary to the wishes of the United Kingdom, Sultan Khalid bin Barghash was named his successor rather than the more pro-British Hamud bin Muhammed. Some reports indicate that the war lasted for a total of 38 minutes.
More facts about short wars: